With the diminishing supply of fossil fuel resources, the use of sustainable and renewable biologically derived feeds is becoming increasingly important for the production of liquid fuels and/or chemicals. The use of such biologically derived feeds may also allow for a more sustainable production of liquid fuels and more sustainable CO2 emissions that may help meet global CO2 emissions standards under the Kyoto protocol. Processes for the conversion of biologically derived materials into fuels and/or chemicals are known in the art.
Catalytic fast pyrolysis is an interesting technology for the conversion of biologically derived materials since it combines the advantages of fast pyrolysis and high product quality. In such a process, solid biomass is first pyrolyzed into volatile organics, gases, and solid coke then the organics upgrade over a catalyst in-situ. Scientists both from academic and industry have done a lot of research in this area.
For example, WO2013/103872 describes a method for pyrolysis of biomass. A two-stage reactor/process is disclosed for conversion of solid particulate biomass material and includes a first stage in which solid particulate biomass material is pyrolyzed to primary reaction products, and a second stage in which the primary reaction products are catalytically converted, which second stage is operated at a temperature higher than that of the first stage. According to WO2013/103872 the wt % yield of liquid bio-oil is higher than the wt % yield produced in a process where the second stage is operated at equal or lower temperature than in the first stage. In the Examples of WO2013/103872 the catalyst used is a phosphorous and zeolite containing catalyst, such as described in ID243US-PRO. Further, it is not clear from WO2013/103872 how exactly the reaction in the Example is performed. In the Examples is not described what exactly the reactor looks like and how the process is carried out, and according to the description of WO2013/103872 a broad range of parameters may be varied in the process.
WO 2013/032672 describes methods for producing fluid hydrocarbon products via catalytic pyrolysis, wherein the reactants comprise solid hydrocarbonaceous materials and hydrogen or a source of hydrogen (e.g. in particular an alcohol). The products may include specific aromatic compounds (e.g. benzene, toluene, naphthalene, xylene, etc.).
Techno-economic analyses have shown that catalytic pyrolysis is a promising technology for biofuel production because of the simple process configuration and promising aromatics yield. An important challenge of this process however is the high cokes formation and the related short lifetime of catalyst. Thus, although several pyrolysis methods have been disclosed in the art, optimization of the conditions is still needed.
The present invention provides a pyrolysis method with a selected set of conditions that leads to an aromatic hydrocarbon product with a very low oxygen content. Also, it was found that coking can be reduced by using a specific carrier gas. Further, by using the conditions of this invention, the lifetime of the catalyst may be increased.